4.4 Genetic modification and clonng

Transcript 4.4 Genetic modification and clonng

Cell Transformation

Recombinant DNA Host Cell DNA Target gene Modified Host Cell DNA

IB Assessment Statement

State two examples of the current uses of genetically modified crops or animals. Examples include salt tolerance in tomato plants, synthesis of beta-carotene (vitamin A precursor) in rice, herbicide resistance in crop plants and factor IX (human blood clotting) in sheep milk.

Genetic Modification

• Because every living organism has DNA, Genes from DNA can be

transferred from one organism to another

• Organisms that have had genes transferred are called

genetically modified organisms.

Genetically Modified Organisms, also called Transgenic Organisms.

• An example, is a transfer of the gene for a resistance to the herbicide glyphosate from a

bacterium to crop plant

, so that the crop can be sprayed with herbicide.

TRANSFORMING BACTERIA

Techniques used in gene transfer into bacteria.

Add a gene into a bacteria is called,

Transforming Bacteria

During transformation, a

cell takes in DNA from outside the cell.

The external DNA becomes a component of the cell's DNA.

Transforming Bacteria

Foreign DNA is first joined to a small,

circular DNA

molecule known as a

plasmid

Plasmids are

found naturally in some bacteria

and have been very useful for

DNA transfer

Steps in inserting a gene into a plasmid: 1. Extract/ Remove gene of interest from a cell

Steps in inserting a gene into a plasmid:

2. Plasmids

are removed from

Bacteria Cells.

3. Plasmids are cut open using

restriction enzymes.

Steps in inserting a gene into a plasmid

4. Sticky ends

are made in the plasmid by adding extra Cytosine Nucleotides to ends.

5. Gene of interest is

insert into plasmid.

Gene of interest Plasmid

Steps in inserting a gene into a plasmid:

6. Ligase enzyme

the plasmid, returning it back to a circle. seals up 7. Plasmids are inserted into

bacteria cells.

8. Bacteria cells with plasmids

& genes of interest are reproduced inside of bacteria.

Steps in inserting a gene into a plasmid:.

8. Bacteria cells with

plasmids & genes

are reproduced inside of bacteria.

of interest

Transforming Bacteria Recombinant DNA Gene for human growth hormone Gene for human growth hormone Human Cell Bacterial chromosome Sticky ends Bacteria cell DNA recombination DNA insertion Plasmid Bacteria cell containing gene for human growth hormone

9. Gene of interest

is extracted from bacteria in bacterial colony.

Transforming Plant Cells Transforming Plant Cells

Transforming Plant Cells

In nature, a bacterium exists that produces

tumors in plant cells.

Researchers can

inactivate the tumor-producing

gene found in this bacterium and

insert a piece of foreign DNA into the plasmid.

The recombinant plasmid can then be used to

infect plant cells

Transforming Plant Cells

When their cell walls are removed, plant cells in culture will sometimes take up

DNA on their own

DNA can also be

injected directly into some cells

Cells transformed by either procedure can be

cultured to produce adult plants.

Gene to be transferred Transforming Plant Cells

Agrobacterium tumefaciens

Cellular DNA Inside plant cell,

Agrobacterium

inserts part of its DNA into host cell chromosome.

Recombinant plasmid Plant cell colonies Transformed bacteria introduce plasmids into plant cells. Complete plant generated from transformed cell.

Transforming Animal Cells Transforming Animal Cells

Many egg cells are large enough that

DNA can be directly injected into the nucleus.

Enzymes may help to insert the foreign DNA

into the chromosomes of the injected cell.

Transforming Animal Cells Recombinant DNA Flanking sequences match host Recombinant DNA replaces target gene Target gene Modified Host Cell DNA

ANIMATION: http://highered.mcgraw hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/12007 8/micro10.swf::Steps%20in%20Cloning%20a%20Gene http://www.sumanasinc.com/scienceinfocus/genetherapy/genetherapy_fla.html

IB Assessment Statement:

Discuss the potential benefits and possible harmful effects of one example of genetic modification.

Benefits and risks of Genetic Modification of food crops Benefits

• Less pest damage and thus more food •Less land is needed •Less need for the use of harmful pesticides.

Risks

•Humans and animals that eat genetically modified food might be harmed • Wild plants might be changed, which could affect the entire ecosystem

Etherpad Activity

Discuss the potential benefits and possible harmful effects of one example of genetic modification in a named organism. (8). 1. salt tolerance in tomato plants, 2. synthesis of beta-carotene (vitamin A precursor) in rice, 3. herbicide resistance in crop plants 4. factor IX (human blood clotting) in sheep milk.

IB Assessment Statement Define clone. Clone: a group of genetically identical organisms or a group of cells derived from a single parent cell.

Outline a technique for cloning using differentiated animal cells.

Clonin g Cloning

clone

is a member of a population of genetically identical cells produced from a single cell.

In 1997, Ian Wilmut cloned a sheep called Dolly.

Dolly and Bonnie Copyright Pearson Prentice Hall

Cloning Dolly Egg Cell Donor Nucleus Fused cell Cloning Embryo Cloned Lamb Foster Mother

Clonin g Cloning Dolly

Clonin g Researchers hope cloning will enable them to make copies of transgenic animals and help save endangered species.

Studies suggest that cloned animals may suffer from a number of genetic defects and health problems.

IB ASSESSMENT STATEMENT

Discuss the ethical issues of therapeutic cloning in humans. Therapeutic cloning is the creation of an embryo to supply embryonic stem cells for medical use.

Virtual Cloning Lab

/ Your turn to clone ! Click on this website, then answer the questions/ address the tasks below: http://learn.genetics.utah.edu/content/tech/cloning/click andclone

• • •

Explain the function of the following things in the process of cloning: Somatic cell donor Egg cell donor Foster Mother

IB Practice Questions -- Cloning What happens to the unfertilized egg used in the cloning process of a differentiated cell?

A. It becomes fertilized.

B. Its nucleus is replaced by the nucleus of the differentiated cell.

C. Its nucleus is fused with the nucleus of the differentiated cell.

D. Its nucleus is exchanged with the nucleus of the sperm.

There are many different views on the ethics of reproductive cloning in humans. Which is a valid argument against cloning in humans?

A. It involves the use of donor sperm which is unethical.

B. It happens naturally when identical twins are conceived.

C. Only females can be cloned.

D. The life expectancy of children produced by cloning might be lower than normal.

Helpful websites on cloning: http://learn.genetics.utah.edu/content/tech/ cloning/whatiscloning/scnt.html

http://learn.genetics.utah.edu/content/tech/ cloning/ http://learn.genetics.utah.edu/content/tech/ cloning/cloningresources/

4.4 Genetic modification and clonng

Transcript 4.4 Genetic modification and clonng

Cell Transformation

Virtual Cloning Lab

END OF SECTION

Directory